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CyberGlove® II system questions
Product registration
Hardware
Performance
Calibration
Demos

CyberTouch™ system questions
Product registration
Hardware
Performance
Calibration
Demos

Product registration

Q. Why should I register my product(s)?

A. Immersion offers a one-year hardware product warranty on all of its interaction products. If you ever need to take advantage of your warranty or need hardware product support, product registration is required.

Note: Extended warranties to cover hardware failures are also available and are strongly recommended.

Q. How do I register my product(s)?

A. There are several ways to register your product. You can complete the product registration form shipped with your product and fax or mail it to Immersion. Alternatively, you can complete the online registration form.

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Q. What is the sensing technology used in the CyberGlove II system? Are the sensors fiber optic or electromagnetic?

A. The CyberGlove II system uses Immersion patented resistive bend-sensing technology, not fiber optic or electromagnetic sensors. The glove sensors have a very linear response and excellent long-term stability. They are also quite insensitive to most external environments. In these ways, they are far superior to fiber optic and electromagnetic sensors.

Q. What are the hardware requirements for using the CyberGlove II device with my system?

A. This is primarily a software question. The CyberGlove II system has only minimal basic requirements. You need a host computer with a USB port. The real question is what do you wish to do with the data once you have it on your host. Displaying graphical hands in real time in a complicated simulated world requires much more processing from the host.

Q. What data rate can I get from a CyberGlove II system?

A. The data rate is 90 Hz with no significant difference getween 18 and 22 sensor versions. In most applications, the data rate from the glove is not the limiting factor. Usually the limit is the host computer's ability to calculate the dynamics and graphics of the application.

Q. What is the difference between the 22-sensor and 18-sensor CyberGlove II systems?

A. The 22-sensor CyberGlove II system has all of the sensors included in the 18-sensor model plus one more sensor on each of the four fingers to measure the angle of the distal joint of each finger. The distal joint is the joint closest to the fingertip.

Q. When is it important to get the 22-sensor CyberGlove II system instead of the 18-sensor model?

A. You should purchase the 22-sensor model if you need accurate measurements of the motion of the distal joint (the joint closest to the fingertip) on each of the four fingers. The 18-sensor model does not have a sensor for measuring this joint. In our VirtualHand® software, we use measurements from the other joints to guess what the distal joint is doing. This works well in many situations. However, it is possible for the distal joint to bend in a way that fools our estimator. For instance, if the other joints are flexed, the software will guess that the distal joint is also flexed, but if you are gripping a real object (as opposed to a simulated one) strongly, it is quite possible that the distal joint is hyperextended instead. With the 22-sensor CyberGlove II system, you have the full information to model this correctly.

Q. What is abduction?

A. Abduction and adduction are the side-to-side motions of the fingers used to spread the fingers apart or close them together. For convenience, we just refer to abduction, though it is more correct to refer to abduction/adduction (one way is spreading, the other closing).

Q. What do the abduction sensors measure relative to?

A. Each abduction sensor measures the angle between the proximal phalanges of the adjacent fingers. The thumb abduction sensor gives the angle between the thumb proximal phalanx and the index metacarpal. Our hand model assumes that there is no appreciable abduction/adduction movement of the metacarpals relative to each other, except for the thumb metacarpal.

Q. What are the switch and LED on the CyberGlove II wristband for?

A. The switch and LED allow the programmer to have an input and output channel from and to the user in VirtualHand APIs. This one-bit custom sensor can be used for a range of user-defined programmable functionalities, such as pause/play simulation and gesture capture recognition.

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Performance

Q. What is the effect of a large magnetic field on the CyberGlove II system?

A. The effect of magnetic fields on the CyberGlove II system will depend on the details of the situation. Magnetic fields in proximity to a CyberGlove II device typically occur when the glove is used with electromagnetic trackers, such as those made by Polhemus and Ascension. We suggest that the glove and its interface module be kept at least 6 inches from Polhemus or Ascension transmitters, electronics units, and power supplies.

If the Polhemus Long Ranger or Ascension Extended Range Transmitter are used, this distance should be increased somewhat. The interface module should also be kept away from other power supplies. If the glove or interface module gets too close to one of these sources, you will see variations in the data, which are often called "jitter." This is due to voltages and accompanying currents induced in the sensors or instrumentation unit by the magnetic field. Note that both Polhemus and Ascension trackers create changing magnetic fields.

Q. What is the resolution of the CyberGlove II system sensors?

A. The resolution of the CyberGlove II system sensors varies depending on their location and their calibration. The factory calibration adjusts the sensitivity of each sensor to optimize the balance between using the full range of the analog-to-digital converters while avoiding the possibility of saturating them over the normal range of motion. This results in a resolution of between 0.5 and 1.0 degree for most of the sensors.

Q. What is the accuracy of the CyberGlove II system?

A. This simple question encompasses several issues that make the answer somewhat complicated. There are a number of elements that contribute to the overall accuracy of the CyberGlove sensors.

1. The sensor itself measures the angle through which it is bent. The angle is that between lines drawn tangent to the ends of the active portion of the sensor. Our measurements on our laboratory tester indicate that the sensor nonlinearity is less than 1%.
2. The fabric of the glove holds the sensors against the user's skin. So the angle being measured is the angle between skin surfaces. This is where it starts to become difficult to say what accuracy is. Many users would like to know where the bones are. In most cases the skin surface tracks the bone surface well, but we have not devised a way to measure the difference between bone positions and skin surface positions. In any case, the exact amounts will vary between users because of differences in the hand shape and tissue movements.
3. Because of manufacturing variations, sensors vary slightly, so calibration is necessary. There are two stages of calibration: hardware and software.

   Hardware calibration is done at our factory. In this stage, we apply a gain and offset to the sensor signal prior to digitizing it. The values are chosen to make optimal use of the 8-bit analog-to-digital converter. We set the values to get as much resolution as possible while also avoiding saturation (values of 1 or 255) near the extremes of motion. Hardware calibration eliminates almost all of the manufacturing variation effects between individual sensors.

Software calibration must be done by the host program (such as our VirtualHand® software). In this stage, another gain and offset are applied to map the raw digital value to an angle in engineering units (radians or degrees) that can be used in geometry calculations. Because of variations in each person's hands, the relationship between the raw values and the angles will be a little different for each person. This affects mostly the offset values. These are normally quite stable, so software calibration information stored on disk can be recalled at a later date and used again. It is common for calibrations to be used for several months without changes.

As you can see, all of these factors make it difficult to give a final, overall accuracy specification. Accuracy depends on how well the user calibrates the glove to their hand and on the actual motion of the user's skin relative to the bones.

Q. Is all the data that is output angular data or is there positional information as well?

A. The CyberGlove II system itself outputs joint angle measurements from the wrist joint down through the fingers. If you need the position and orientation of the forearm (which, combined with the joint angles would let you calculate the position of the fingertips, for instance), you should consider using an electromagnetic tracker with your glove. The CyberGlove II system has mounting provisions for both Ascension and Polhemus trackers on the wristband (that moves with the forearm). Given the joint angles measured by the CyberGlove II system, and the position and orientation of the forearm from an electromagnetic tracker, you can use functions from our VirtualHand software to calculate the position of any particular point on the hand surface.

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Calibration

Q. What is the procedure for adjusting the calibration of the CyberGlove II system for the best accuracy?

A. If you are using the Device Configuration Utility (DCU) to do the calibration, you should start from the default calibration file that was shipped with your glove. You should mostly end up adjusting offsets and doing very little adjustment of gains.

With the DCU, start by making the hand straight and adjusting the flexion offsets of the four fingers to make the hand on the screen also look straight. Then curl the fingers into a fist and, if necessary, adjust the finger flexion gains to make the fist on the screen match the user's hand. Then touch the thumb tip to the index finger tip. Adjust the thumb rotation sensor offset to make the thumb tip cross over till it is in line with the index finger tip. Touch the thumb tip to the middle finger tip and adjust the thumb rotation sensor gain slightly, if necessary. You may need to make several iterations between gain and offset adjustments for the thumb rotation to get the motion to match. Try to use the minimum gain needed to get the thumb in line with the index and middle fingers.

Once the thumb lines up with the fingertips, adjust the thumb abduction offset and/or the finger flexion gains or offsets to get the tips to actually touch the thumb tip. If the thumb is too far away on all fingers, you'll probably want to adjust the thumb abduction. If one finger is farther away, you'll probably want to adjust that finger's flexion. Be sure to double check that the thumb abduction is reasonable by holding the hand flat and then abducting the thumb to a right angle from the fingers. The positions should look reasonable.

It is usually difficult to get the ring and especially the little finger tip to touch the thumb tip. This is partly due to the fact that the DCU hand model does not make use of the palm arch sensor. On the real hand, arching of the palm brings the ring and pinkie closer to the thumb.

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Demos

Q. Where can I see and test your products before making a purchase?

A. We can arrange a demonstration of our products at our office in San Jose, California, or you can contact one of our resellers in your area. Contact our sales department to arrange a meeting.

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CyberTouch™ system questions

Product registration

Q. Why should I register my product(s)?

A. Immersion offers a one-year hardware product warranty on all of its interaction products. If you ever need to take advantage of your warranty or need hardware product support, product registration is required.

Note: Extended warranties to cover hardware failures are also available and are strongly recommended.

Q. How do I register my product(s)?

A. There are several ways to register your product. You can complete the product registration form shipped with your product and fax or mail it to Immersion. Alternatively, you can complete the online registration form.

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CyberTouch hardware

Q. What is the sensing technology used in the CyberTouch system? Are the sensors fiber optic or electromagnetic?

A. The CyberTouch system uses Immersion patented resistive bend-sensing technology, not fiber optic or electromagnetic sensors. The glove sensors have a very linear response and excellent long-term stability. They are also quite insensitive to most external environments. In these ways, they are far superior to fiber optic and electromagnetic sensors.

Q. What are the hardware requirements for using the CyberTouch device with my system?

A. This is primarily a software question. The CyberTouch system has only minimal basic requirements. You need a host computer with an RS-232 port. The real question is what do you wish to do with the data once you have it on your host. Displaying graphical hands in real time in a complicated simulated world requires much more processing from the host.

Q. What data rate can I get from a CyberTouch system?

A. With the CyberTouch system communicating at 115200 baud, you can get more than 90 full 18-sensor records per second. In most applications, the data rate from the glove is not the limiting factor. Usually the limit is the host computer's ability to calculate the dynamics and graphics of the application.

Q. What is abduction?

A. Abduction and adduction are the side-to-side motions of the fingers used to spread the fingers apart or close them together. For convenience, we just refer to abduction, though it is more correct to refer to abduction/adduction (one way is spreading, the other closing).

Q. What do the abduction sensors measure relative to?

A. Each abduction sensor measures the angle between the proximal phalanges of the adjacent fingers. The thumb abduction sensor gives the angle between the thumb proximal phalanx and the index metacarpal. Our hand model assumes that there is no appreciable abduction/adduction movement of the metacarpals relative to each other, except for the thumb metacarpal.

Q. What is the maximum frequency of the CyberTouch actuator?

A. The maximum frequency of the actuator vibration is 125 Hz.

Q. When I use the "A" command, what is the relationship between the value of v and the frequency of the CyberTouch actuators?

A. The voltage applied to the actuator is linearly proportional to the command value. A command value of 255 will cause vibration at 125 Hz. Due to friction in the actuator, however, the command must generally be 50 or higher for the actuator to begin vibrating.

Q. Can I get a 22 sensor CyberGlove system with a CyberTouch option?

A. No, for technical reasons, we cannot offer a 22-sensor CyberGlove system with the CyberTouch option at this time.

Q. What are the switch and LED on the CyberTouch wristband for?

A. The switch and LED allow the programmer to have an input and output channel from and to the user. In VirtualHand APIs. This one-bit custom sensor can be used for a range of user-defined programmable functionalities, such as pause/play simulation and gesture capture recognition.

Top of Page

Performance

Q. What is the effect of a large magnetic field on the CyberTouch system?

A. The effect of magnetic fields on the CyberTouch system will depend on the details of the situation. Magnetic fields in proximity to a CyberTouch device typically occur when the glove is used with electromagnetic trackers, such as those made by Polhemus and Ascension. We suggest that the glove and its interface module be kept at least 12 inches from Polhemus or Ascension transmitters, electronics units, and power supplies.

If the Polhemus Long Ranger or Ascension Extended Range Transmitter are used, this distance should be increased somewhat. The interface module should also be kept away from other power supplies. If the glove or interface module gets too close to one of these sources, you will see variations in the data, which are often called "jitter." This is due to voltages and accompanying currents induced in the sensors or instrumentation unit by the magnetic field. Note that both Polhemus and Ascension trackers create changing magnetic fields.

Q. What is the resolution of the CyberTouch system sensors?

A. The resolution of the CyberTouch system sensors varies depending on their location and their calibration. The factory calibration adjusts the sensitivity of each sensor to optimize the balance between using the full range of the analog-to-digital converters while avoiding the possibility of saturating them over the normal range of motion. This results in a resolution of between 0.5 and 1.0 degree for most of the sensors. Resolution for the abduction sensors is finer. If the user is interested in a smaller range of motion, the factory calibration can be overridden in software. Refer to the 'C' command in your CyberTouch system manual.

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Calibration

Q. What is the procedure for adjusting the calibration of the CyberTouch system for the best accuracy?

A. If you using the Device Configuration Utility (DCU) to do the calibration, you should start from the default calibration file that was shipped with your glove. You should mostly end up adjusting offsets and doing very little adjustment of gains.

With the DCU, start by making the hand straight and adjusting the flexion offsets of the four fingers to make the hand on the screen also look straight. Then curl the fingers into a fist and, if necessary, adjust the finger flexion gains to make the fist on the screen match the user's hand. Then touch the thumb tip to the index finger tip. Adjust the thumb rotation sensor offset to make the thumb tip cross over till it is in line with the index finger tip. Touch the thumb tip to the middle finger tip and adjust the thumb rotation sensor gain slightly, if necessary. You may need to make several iterations between gain and offset adjustments for the thumb rotation to get the motion to match. Try to use the minimum gain needed to get the thumb in line with the index and middle fingers.

Once the thumb lines up with the fingertips, adjust the thumb abduction offset and/or the finger flexion gains or offsets to get the tips to actually touch the thumb tip. If the thumb is too far away on all fingers, you'll probably want to adjust the thumb abduction. If one finger is farther away, you'll probably want to adjust that finger's flexion. Be sure to double check that the thumb abduction is reasonable by holding the hand flat and then abducting the thumb to a right angle from the fingers. The positions should look reasonable.

It is usually difficult to get the ring and especially the little finger tip to touch the thumb tip. This is partly due to the fact that the DCU hand model does not make use of the palm arch sensor. On the real hand, arching of the palm brings the ring and pinkie closer to the thumb.

Top of Page

Demos

Q. Where can I see and test your products before making a purchase?

A. We can arrange a demonstration of our products at our office in San Jose, California, or you can contact one of our resellers in your area. Contact our sales department to arrange a meeting.